Subtonsillar placement of auditory brainstem implant.

A 26-year-old female with NF2 underwent removal of an acoustic schwannoma via extended retrosigmoid approach with subtonsillar placement of the auditory brainstem implant. The patient had already shown palsy of the lower cranial nerves on the opposite side due to previous surgery. Differing from conventional routes such as the translabyrinthine and the retrosigmoid, the subtonsillar approach enabled us to observe the entire cochlear nucleus and avoid injury to the 9th and 10th cranial nerves when applying the electrode. Hearing in pure tone average was maintained almost at the preoperative level. We present a new use of this approach in placing the electrode and discuss its advantages.